SB M20-345

[EricJ]

25 minutes ago, Shadrach said:

True if his counterweight passed visual inspection.  Given it's appearance (deep cracks) in the uploaded image there is a strong argument that it does not meet "condition for safe operation" per 14 CFR 3.5(a).

That is subjective, though.   Without being a metallurgist I wouldn't judge the likelihood of failure of that, and I haven't heard of any actually failing.   The pilot determines airworthiness, so it really is a judgement call both legally and practically.

[Shadrach]

4 minutes ago, EricJ said:

That is subjective, though.   Without being a metallurgist I wouldn't judge the likelihood of failure of that, and I haven't heard of any actually failing.   The pilot determines airworthiness, so it really is a judgement call both legally and practically.

I am an advocate for the lightest regulatory hand as is legally possible, which I realize is subjective.  However, given that the factory has released an SB with high resolution photographs of the unairworthy conditions associated with the hybrid weight, I don't think one need be a metallurgist.  Claiming airworthiness due to ignorance of metallurgy seems like a tough position to take.  I certainly wouldn't want to defend such a decision if there was a failure. 

[A64Pilot]

It’s an SB, so those that want to take the legal out are free to do so, SB’s aren’t mandatory, just often a good idea.

However most AD’s are birthed from SB’s etc., and I bet this one has a good chance on becoming an AD, if it does I think it unlikely the parts will be easier or less expensive to be had than now and of course an AD grounds you.

I think not replacing a suspect weight would be foolish, but that’s just my opinion. Flutter scares me, it’s one of those things that if it happens often it doesn’t matter how good you are, it can be over in less than 1 sec.

[tony]

20 hours ago, Shadrach said:

I am an advocate for the lightest regulatory hand as is legally possible, which I realize is subjective.  However, given that the factory has released an SB with high resolution photographs of the unairworthy conditions associated with the hybrid weight, I don't think one need be a metallurgist.  Claiming airworthiness due to ignorance of metallurgy seems like a tough position to take.  I certainly wouldn't want to defend such a decision if there was a failure. 

Where's the math that says the probability of failure, for the next flight is greater than 1x10-9 for a 60 year old airplane? Fix before flight is ridiculous, especially when there is no solution to the problem   This is just as good as the trim hinge AD that came out a few years ago.  Its only a matter of time before the FAA turns this piece of non engineering into another AD.  Yes I'm annoyed.  

[Shadrach]

3 hours ago, tony said:

Where's the math that says the probability of failure, for the next flight is greater than 1x10-9 for a 60 year old airplane? Fix before flight is ridiculous, especially when there is no solution to the problem   This is just as good as the trim hinge AD that came out a few years ago.  Its only a matter of time before the FAA turns this piece of non engineering into another AD.  Yes I'm annoyed.  

You could say that about areas of corrosion found anywhere on the airframe....and it'd be true as there is no question there are many aircraft out there flying around with undetected corrosion. It's only when one has verifiable structural failure or said corrosion is discovered that we take notice.  On this forum we've literally seen tons of planes condemned that were operating beautifully just days before they became salvage.  They would have continued in service for quite sometime with no one the wiser if the rot was not discovered.

To each there own...my take is if

1) If you have a bird with hybrid weights that show no signs deterioration, I'd say go fly without hesitation. 

2) If you have a bird with hybrid weights that show cracks, bulges and obvious signs of deterioration, I'd say it’d be a good idea to consider not only the risks but if your understanding of the risks is adequate.  Maybe limit the aircraft to pattern work until a solution is found.

3) If you've a bird with hybrid weights that show cracks, bulges and obvious signs of deterioration...and you've posted detailed images on the internet of the cracked and bulged weights that match the the images and definition of the unairworthy condition put forth by the factory in the the SB, I'd say revisit #2 with greater vigor and consideration.

[67 m20F chump]

Exchanged voicemail with Frank at Mooney today.  His best guess is new weights Feb/March 23’.  Just passing it along.

 

[M20F-1968]

For what it is worth, my aircraft is an early 1968 F.  The elevators on it have the solid lead weights and not the ones with inserts.  For about two seconds only I thought for about the possibility that the paint might be covering up evidence of the inserts but I severely doubt that to be the case.  

John Breda

[N201MKTurbo]

13 minutes ago, M20F-1968 said:

For what it is worth, my aircraft is an early 1968 F.  The elevators on it have the solid lead weights and not the ones with inserts.  For about two seconds only I thought for about the possibility that the paint might be covering up evidence of the inserts but I severely doubt that to be the case.  

John Breda

It seems to me that if paint is obscuring the inserts, there is no problem. Tinning steel with lead is an effective method of corrosion protection, like galvanizing,  so casting steel inserts into lead doesn’t necessarily spell disaster. I have to think that it was a failure of surface prep on the steel inserts that kept the lead from bonding to the steel. Or the steel was too cold and formed a cold solder joint kind of thing. This doesn’t mean that all the castings failed to bond. There could be castings that will last forever without issue.

[M20F-1968]

On 11/26/2022 at 11:09 AM, N201MKTurbo said:

It seems to me that if paint is obscuring the inserts, there is no problem. Tinning steel with lead is an effective method of corrosion protection, like galvanizing,  so casting steel inserts into lead doesn’t necessarily spell disaster. I have to think that it was a failure of surface prep on the steel inserts that kept the lead from bonding to the steel. Or the steel was too cold and formed a cold solder joint kind of thing. This doesn’t mean that all the castings failed to bond. There could be castings that will last forever without issue.

The real answer is that there is no suggestion of an interface of lead and steel.  The paint is completely smooth and I doubt very much that my weights are anything but a piece of solid lead.

John Breda

[A64Pilot]

1 hour ago, M20F-1968 said:

The real answer is that there is no suggestion of an interface of lead and steel.  The paint is completely smooth and I doubt very much that my weights are anything but a piece of solid lead.

John Breda

I’m going to go out on a limb and say maybe a good strong magnet would tell for sure and of course be non destructive

[Shadrach]

On 11/26/2022 at 10:48 AM, M20F-1968 said:

For what it is worth, my aircraft is an early 1968 F.  The elevators on it have the solid lead weights and not the ones with inserts.  For about two seconds only I thought for about the possibility that the paint might be covering up evidence of the inserts but I severely doubt that to be the case.  

John Breda

My bird came off the line in June of 1967.  Mine has non hybrid weights so  it’s almost guaranteed that yours is the same.

[N201MKTurbo]

And in another 50 years, we will know if the replacement weights are any better….

[Shadrach]

19 minutes ago, N201MKTurbo said:

And in another 50 years, we will know if the replacement weights are any better….

Wait, we have replacement weights?

[N201MKTurbo]

13 minutes ago, Shadrach said:

Wait, we have replacement weights?

As Christmas presents, or was it Memorial Day presents?

[67 m20F chump]

Easter bunny may bring it if we are lucky.

 

[Kelpro999]

7 hours ago, bluehighwayflyer said:

This SB does not apply to my Mooney, but today while wiping down the leading edges a thought occurred.  What about the rudders on the affected Mooneys?   Are they not the same?   My rudder and elevator counterweights appear to be constructed and attached in identically the same manner except that the elevator counterweights are attached with 3 rivets and the rudder counterweight is attached with four.  I am sure that mine are original.  

 They are nearly identical forward (visible area). Attachment area mimic the rivet layout. I didn’t answer your question about bi-metal because I have no idea.

Edited December 4, 2022 by Kelpro999

[Grandmas Flying Couch]

Looks like I dodged this particular bullet: #670200

Thank God, I'm just getting my engine rehung!  

[Will.iam]

On 10/8/2022 at 1:32 PM, Pinecone said:

Need to make sure they are the same weight (as in ounces).

There is a difference in them from a 252 to an Encore.

Not to sidetrack this thread more that it has but changing the weights on an encore conversion puzzles me as to why? Since the only things that change is weight and 10 hp more, the VNE and speeds are the same as are the controls and hinge points. If the weights are to control flutter, why would a weight increase cause that? 252’s can get a ferry permit to fly overgross weight as can an encore or any model mooney for that matter and they don’t change the weights for those flights. I just don’t understand the logic behind increasing the weights as if they were needed for the encores speed then the same weights should be needed for the 252. When the ovations increase their engines from 280hp to 310hp is the weights increased there as well? Just curious if any of the aeronautical engineers on here can shed some light in laymans terms why the weight change. 

[Aerodon]

19 minutes ago, Will.iam said:

Not to sidetrack this thread more that it has but changing the weights on an encore conversion puzzles me as to why? Since the only things that change is weight and 10 hp more, the VNE and speeds are the same as are the controls and hinge points. If the weights are to control flutter, why would a weight increase cause that? 252’s can get a ferry permit to fly overgross weight as can an encore or any model mooney for that matter and they don’t change the weights for those flights. I just don’t understand the logic behind increasing the weights as if they were needed for the encores speed then the same weights should be needed for the 252. When the ovations increase their engines from 280hp to 310hp is the weights increased there as well? Just curious if any of the aeronautical engineers on here can shed some light in laymans terms why the weight change. 

FWIW, the story I heard that makes sense was that when Mooney developed the Encore, they took the parts on hand from the long body production line and just used those.   I got most of my parts for the conversion off a 1996 M20M.

Aerodon

 

[Pinecone]

That makes sense.   Or at least, the saw no reason to make, stock, and install different weights, and standardized them.

In that case, they are not really required to fly safely, to comply with the factory drawings, you need them.

[Will.iam]

I can see how that would save production cost but sad to see that weight savings was not the priority if indeed that was the main reason. 

[EricJ]

Is there any update on the latest disposition of this?   Have any weights been replaced with new or are people finding used stuff or just flying anyway?

[Kelpro999]

On 1/3/2023 at 9:29 PM, Will.iam said:

Not to sidetrack this thread more that it has but changing the weights on an encore conversion puzzles me as to why? Since the only things that change is weight and 10 hp more, the VNE and speeds are the same as are the controls and hinge points. If the weights are to control flutter, why would a weight increase cause that? 252’s can get a ferry permit to fly overgross weight as can an encore or any model mooney for that matter and they don’t change the weights for those flights. I just don’t understand the logic behind increasing the weights as if they were needed for the encores speed then the same weights should be needed for the 252. When the ovations increase their engines from 280hp to 310hp is the weights increased there as well? Just curious if any of the aeronautical engineers on here can shed some light in laymans terms why the weight change. 

Perhaps there was a collision of natural response frequency between new HP and flight control masses. Just a thought but probably too far out there